Ozempic and GLP-1 lawsuit MDL 3094: where the gastroparesis and NAION litigation actually stands

The GLP-1 receptor agonist litigation is among the fastest-growing pharmaceutical mass torts in active development. MDL 3094 (In re: Glucagon-Like Peptide-1 Receptor Agonists (GLP-1 RAs) Products Liability Litigation), centralized in the U.S. District Court for the Eastern District of Pennsylvania before Judge Karen Spencer Marston, consolidates approximately 3,636 federal cases as of May 2026 alleging that GLP-1 medications cause severe gastrointestinal injuries including gastroparesis (stomach paralysis), ileus, intestinal obstruction, and gallbladder disease. A separate MDL 3163 in the same district before the same judge covers non-arteritic anterior ischemic optic neuropathy (NAION) vision loss cases, with 86 cases pending as of May 2026 and a Science Day scheduled for June 2, 2026. The defendants are Novo Nordisk (manufacturer of Ozempic, Wegovy, and Rybelsus, all containing semaglutide) and Eli Lilly (manufacturer of Mounjaro and Zepbound, containing tirzepatide).

The procedural posture in mid-2026 reflects active discovery without bellwether trial selection completed. Judge Marston assumed oversight of MDL 3094 after Judge Pratter's unexpected passing in May 2024. Judge Marston's August 15, 2025 evidentiary ruling established that gastroparesis claims require objective diagnostic evidence — specifically, gastric emptying studies confirming abnormal retention times. The ruling excluded alternative evidence (CT scans, MRIs, endoscopy, ultrasound findings, barium studies, or temporal symptom correlation) as insufficient for causation purposes. The ruling has substantially affected case qualification — plaintiffs without gastric emptying study results face material weakness in their cases.

The litigation's substantive theory focuses on adequate warning. GLP-1 medications were initially approved for diabetes treatment but became wildly popular for off-label weight loss use, eventually leading to FDA-approved weight loss indications (Wegovy in 2021; Zepbound in 2023). The medications work by slowing gastric emptying — the same mechanism that produces weight loss can produce severe gastroparesis in some patients. The plaintiffs allege that Novo Nordisk and Eli Lilly knew or should have known about the increased gastroparesis risk and failed to adequately warn patients and prescribers. A 2023 JAMA Internal Medicine study linked GLP-1 medications to substantially increased risk of gastroparesis. A 2024 VA study supports the NAION risk connection.

The total exposure is potentially substantial. Legal experts project settlement values of $400,000-$700,000 for severe gastroparesis cases involving gallbladder removal or other significant complications, with NAION cases potentially exceeding $1 million due to permanent blindness. Total liability across the litigation could exceed $2 billion. With cases continuing to grow (more than 100 new GLP-1 lawsuits filed in early May 2026 alone), the litigation is positioned to become one of the largest active pharmaceutical mass torts. Bellwether trials are expected to begin in late 2026 or 2027.

This is the science behind the GLP-1 injury theories, the procedural history of MDLs 3094 and 3163, the eligibility framework including the gastric emptying study requirement, the strategic considerations for prospective plaintiffs, and how the litigation compares to other recent pharmaceutical mass torts.

What GLP-1 receptor agonists are

GLP-1 receptor agonists are a class of medications originally developed for type 2 diabetes treatment:

Mechanism of action. GLP-1 (glucagon-like peptide-1) is a naturally occurring hormone that regulates blood glucose and appetite. Synthetic GLP-1 receptor agonists activate the same receptors, producing several effects:

Increased insulin secretion (improving diabetes control)
Decreased glucagon secretion
Slowed gastric emptying (food remains in stomach longer)
Increased satiety (feeling of fullness)
Reduced appetite

The slowed gastric emptying is central to the medications' weight loss effects — patients feel fuller longer and consume less food. But the same mechanism creates the alleged injury risk: in some patients, gastric emptying slows excessively, producing gastroparesis.

The major medications:

Ozempic (semaglutide, Novo Nordisk). FDA-approved 2017 for type 2 diabetes. Weekly injection. Became wildly popular off-label for weight loss starting around 2020.

Wegovy (semaglutide, Novo Nordisk). Same active ingredient as Ozempic but at higher doses. FDA-approved 2021 for chronic weight management.

Rybelsus (semaglutide, Novo Nordisk). Oral semaglutide. FDA-approved 2019 for type 2 diabetes.

Mounjaro (tirzepatide, Eli Lilly). Dual GIP/GLP-1 receptor agonist. FDA-approved 2022 for type 2 diabetes.

Zepbound (tirzepatide, Eli Lilly). Same active ingredient as Mounjaro at weight loss-optimized dosing. FDA-approved 2023 for chronic weight management.

The medications have produced substantial commercial success. Novo Nordisk became Europe's largest company by market capitalization based largely on Ozempic and Wegovy sales. Eli Lilly's stock similarly benefited from Mounjaro and Zepbound success. The financial scale of the manufacturers means substantial resources available for both defense and potential settlement.

The alleged injuries

The MDL 3094 cases involve various injury categories:

Gastroparesis ("stomach paralysis"). The signature injury claim. Severe slowing of gastric emptying produces:

Chronic nausea
Severe vomiting (sometimes requiring hospitalization)
Abdominal pain and bloating
Malnutrition from inability to maintain adequate caloric intake
Inability to digest solid foods
Need for special diets or feeding modifications
In some cases, gastric pacemaker implantation or surgical intervention

Intestinal obstruction (ileus). Reduced gastrointestinal motility can produce intestinal blockage, requiring:

Emergency hospitalization
Sometimes surgical intervention
Risk of bowel perforation or other complications

Gallbladder disease. Some plaintiffs developed gallbladder problems requiring:

Cholecystectomy (gallbladder removal)
Treatment for gallstones
Treatment for cholecystitis (gallbladder inflammation)

Pancreatitis. Inflammation of the pancreas requiring medical intervention.

Cyclic vomiting syndrome. Recurrent episodes of severe vomiting.

Kidney complications. Various kidney issues reported.

Other gastrointestinal complications. Severe nausea, vomiting, and dehydration requiring hospitalization.

The MDL 3163 cases involve a specific eye injury:

Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION). A condition causing sudden, often permanent vision loss in one or both eyes. The mechanism may involve:

Reduced blood flow to the optic nerve
Ischemic damage to optic nerve fibers
Permanent vision impairment in the affected eye(s)

NAION typically affects 1 in 10,000 users by some estimates, but the severity of injury (often permanent blindness in the affected eye) produces substantial damages.

Severity considerations. Cases with surgical intervention (gallbladder removal, gastric pacemaker, bowel surgery) or permanent disability (NAION, persistent gastroparesis requiring ongoing intervention) typically produce higher settlement values than cases involving temporary injuries.

The procedural history of MDL 3094

The litigation has developed:

2023. First Ozempic gastroparesis lawsuits filed in various jurisdictions. JAMA Internal Medicine study published linking GLP-1 medications to gastroparesis risk.

September 2024. Judicial Panel on Multidistrict Litigation consolidated federal Ozempic and other GLP-1 cases into MDL 3094 in the Eastern District of Pennsylvania. Originally assigned to Judge Pratter.

May 2024. Judge Pratter passed away unexpectedly. Judge Karen Spencer Marston assumed oversight of the MDL.

Throughout 2024-2025. Active discovery including document production from Novo Nordisk and Eli Lilly, expert reports, and case management orders.

August 15, 2025. Judge Marston's landmark evidentiary ruling. The ruling established:

Gastroparesis claims require objective diagnostic evidence
Specifically, gastric emptying studies showing abnormal retention times
Alternative evidence (CT scans, MRIs, endoscopy, etc.) insufficient
Plaintiffs without GES evidence face material case weakness

The ruling substantially affected case qualification. Many existing plaintiffs and counsel scrambled to obtain proper diagnostic testing.

October-December 2025. Fact discovery closure (October 2025) and expert report deadlines (December 2025) per case management orders.

Throughout 2025. Case count grew from approximately 1,800 (mid-2025) to approximately 3,546 (April 2026).

Early 2026. Bellwether case selection process beginning. Judge Marston emphasized maintaining litigation momentum while ensuring thorough discovery processes.

June 2, 2026. Science Day scheduled for NAION cases — comprehensive scientific evidence presentation about the connection between GLP-1 medications and NAION.

Mid-2026. Bellwether selection expected to be finalized. First bellwether trials anticipated late 2026 or 2027.

Parallel state court litigation. New Jersey established a multicounty litigation (MCL) for NAION cases. Various state court filings throughout the country.

The current procedural phase emphasizes:

Establishing general causation evidence (whether GLP-1 medications can cause the alleged injuries)
Resolving scientific disputes about long-term gastrointestinal damage
Preparing bellwether cases for trial
Coordinated discovery across federal and state proceedings

Eligibility framework

The framework for filing GLP-1 cases:

Documented GLP-1 medication use. Records showing the claimant used Ozempic, Wegovy, Rybelsus, Mounjaro, or Zepbound (or similar GLP-1 medications). Prescription records, pharmacy records, insurance claims documentation.

Duration considerations. Generally requires substantial use period (months to years) to establish causation. Very brief use is less likely to produce the cumulative injury patterns supporting case theories.

Documented qualifying injury:

For gastroparesis claims under post-August 2025 ruling:

Gastric Emptying Study (GES) showing abnormal retention times — THIS IS NOW REQUIRED
Wireless motility capsule study (alternative GES method)
Other objective testing methods specifically authorized by the court
NOT sufficient under current ruling: CT scans, MRIs, endoscopy, ultrasound, barium studies, or temporal symptom correlation alone

For other gastrointestinal injuries:

Medical records documenting ileus, intestinal obstruction, gallbladder disease, pancreatitis, or other qualifying conditions
Treatment records including any surgical interventions
Hospital admission records for severe presentations

For NAION claims:

Ophthalmology records documenting NAION diagnosis
Visual field testing
Optical coherence tomography (OCT) imaging
Documentation of sudden vision loss onset

Temporal connection. The injury developed during or shortly after GLP-1 medication use. Pre-existing conditions of the same type weaken the case substantially.

No significant alternative causation. Cases with strong alternative explanations (pre-existing diabetic gastroparesis, prior NAION events from other causes, etc.) face more difficult causation analysis. The plaintiff doesn't need to show GLP-1 was the sole cause, but the case is stronger when alternative causes are less prominent.

Statute of limitations compliance. State-specific limitations periods apply. Many states have 2-3 year limitation periods. The discovery rule may provide some flexibility but has limits.

Age limitation. Most firms require plaintiffs under 75 due to causation complexity for elderly plaintiffs with multiple potential alternative causes.

The strongest typical case profile:

A patient who used Ozempic, Wegovy, or another GLP-1 medication for at least 6 months, was diagnosed with severe gastroparesis through a gastric emptying study, required medical intervention beyond outpatient management (hospitalization, surgical procedures, gastric pacemaker, ongoing specialized treatment), has comprehensive medical records establishing the timeline, and has no significant alternative causation factors.

How the gastric emptying study requirement changes things

The August 2025 ruling requiring gastric emptying study evidence substantially affects the litigation:

Pre-ruling case qualification. Many existing plaintiffs had been qualified based on symptoms, clinical diagnosis, and imaging short of formal GES testing. The pre-ruling qualification standards were more permissive.

Post-ruling case qualification. Plaintiffs without GES evidence may need to:

Obtain GES testing now (years after injury onset, which can complicate the evidence)
Have their cases re-evaluated for continued viability
Potentially face case dismissal if GES results don't confirm gastroparesis
Consider alternative injury claims (gallbladder, NAION, etc.) if GES doesn't support gastroparesis

Strategic implications. Counsel pursuing GLP-1 cases must now:

Verify GES evidence before case acceptance
Coordinate with treating physicians to obtain proper testing
Document the timeline of testing relative to medication use
Address GES result interpretation in case strategy

Impact on case values. Cases with strong GES evidence command higher settlement values than cases relying on symptoms alone. The objective evidence requirement substantially affects case strength.

The ruling represents Judge Marston's effort to ensure that the MDL focuses on cases with objective scientific support. The framework has both benefits (focuses litigation on strongest cases) and costs (excludes cases that may have legitimate injuries without proper diagnostic testing).

Settlement projections

Settlement projections vary substantially by case category:

Severe gastroparesis with gallbladder removal: $400,000-$700,000 per case based on early case valuations. The combination of gastroparesis with surgical complications produces substantial damages.

Gastroparesis with ongoing medical treatment: $250,000-$500,000 for cases with persistent symptoms requiring ongoing care.

Less severe gastrointestinal injuries: $100,000-$300,000 for cases with documented injuries but less extensive treatment requirements.

NAION cases: Potentially $1 million+ given the permanent vision loss involved. Cases with bilateral NAION (vision loss in both eyes) would command even higher values.

Total litigation exposure: Estimated $2+ billion across the litigation. Novo Nordisk and Eli Lilly both have substantial financial capacity for resolution.

Bellwether-dependent. Final settlement framework depends on bellwether outcomes expected in late 2026 or 2027. Strong plaintiff verdicts could accelerate settlement; defense verdicts could delay or reduce settlements.

Time horizon. Given the litigation's early stage, global settlement is likely 2-4 years away at minimum. Patient navigation of the extended timeline is required.

How GLP-1 litigation compares to other mass torts

The litigation has distinctive features:

Compared to NEC infant formula MDL 3026 with substantial state court verdicts: NEC has produced $625M+ in plaintiff verdicts. GLP-1 hasn't yet reached bellwether trials. Both involve products with substantial commercial success and serious alleged injuries.

Compared to Suboxone MDL 3092 with extended bellwether timeline: Both involve pharmaceutical products with allegedly delayed warnings. Suboxone has 11,000+ cases with bellwether trials projected for 2028. GLP-1 has fewer cases but faster trajectory.

Compared to Tepezza MDL 3079 with bellwethers starting August 2026: Both involve pharmaceutical products with relatively recent FDA-approved indications. Tepezza is smaller (~275 cases); GLP-1 is much larger.

Compared to Paragard IUD MDL 2974 with the defense bellwether verdict: Both involve products marketed to specific populations. Paragard faces post-defense-verdict reduced leverage. GLP-1 is earlier in trajectory with leverage to be determined by bellwether outcomes.

Compared to Roundup litigation with $11+ billion in settlements: Both involve products with substantial documented internal corporate knowledge. Roundup is procedurally further along; GLP-1 is earlier.

Compared to Zantac MDL 2924 dismissed on Daubert grounds: Zantac plaintiffs faced catastrophic expert exclusion. GLP-1 has survived initial Daubert challenges with Judge Marston's evidentiary ruling shaping the framework.

The broader procedural framework for mass tort settlements is detailed in our overview of how mass tort litigation works. GLP-1 represents one of the most rapidly growing mass torts with substantial total exposure but uncertain ultimate resolution timeline.

Strategic considerations

For potential plaintiffs:

Obtain gastric emptying study immediately if not already done. The August 2025 ruling makes GES evidence essentially required for gastroparesis claims. Patients with gastroparesis symptoms but without GES testing should pursue testing through their treating gastroenterologists.

Engage experienced GLP-1 counsel. The MDL is procedurally specific with evolving evidentiary standards. Counsel with established GLP-1 case experience handles cases more effectively. Most plaintiffs' firms work on contingency basis (typically 30-40% of recovery).

Document the medication timeline thoroughly. Records of:

Initial prescription
Pharmacy fill records showing duration of use
Insurance claims documentation
Off-label use documentation (if applicable)
Date of cessation (if discontinued)

Document the injury timeline thoroughly. Records of:

Symptom onset relative to medication use
All medical evaluations
All diagnostic testing (GES is now essential for gastroparesis)
Treatment provided and ongoing
Hospitalizations and surgical interventions

Consider multiple injury types. Some plaintiffs have multiple GLP-1 related injuries (gastroparesis + gallbladder + NAION). Coordinated claims may be appropriate.

Watch the June 2026 Science Day for NAION cases. The comprehensive scientific evidence presentation will substantially affect NAION case framework. NAION plaintiffs should monitor outcomes.

Don't accept inadequate settlements pre-bellwether. Some firms may offer early settlements before bellwether trials affect pricing. Have any settlement offer evaluated by experienced counsel.

Be realistic about timeline. Bellwether trials expected late 2026 or 2027. Global settlement (if reached) likely 2027-2029. Plan for extended litigation timelines. Continuing medical treatment during the wait will be necessary for many plaintiffs.

Coordinate with treating physicians. Gastroenterologists, ophthalmologists, and other treating specialists are important witnesses. Their support for the case theory strengthens the case substantially.

Consider state court alternatives. State court filings may proceed faster than federal MDL in some jurisdictions. The strategic analysis depends on case specifics.

Watch for additional defendants. Beyond Novo Nordisk and Eli Lilly, other GLP-1 manufacturers (or compounded GLP-1 products from compounding pharmacies) may face liability. Comprehensive case analysis identifies all potentially responsible parties.

The GLP-1 receptor agonist litigation represents accountability for one of the most commercially successful pharmaceutical categories in recent history. The medications produced enormous benefits for diabetes management and weight loss while allegedly causing serious gastrointestinal and ocular injuries in a meaningful subset of patients. The substantial commercial success of the medications combined with the documented adverse effects creates the conditions for substantial mass tort litigation. The August 2025 evidentiary ruling has substantially shaped case qualification by requiring objective diagnostic evidence. The bellwether trial framework expected to develop through 2026-2027 will determine settlement value framework. For potential plaintiffs whose serious injuries developed during or shortly after GLP-1 medication use, the framework provides paths to compensation that require proper documentation, experienced counsel, and patience with the extended timeline. The work for plaintiffs is engagement with qualified counsel familiar with the post-August 2025 evidentiary framework, comprehensive medical documentation including gastric emptying study evidence for gastroparesis claims, careful coordination with treating physicians, and informed decision-making throughout the extended litigation timeline.